1. Field of the Invention
The present invention relates to a seat used in a vehicle, such as an automobile, and more particularly, to an occupant discriminating method therefor.
2. Description of the Related Art
According to a known method that is described in Jpn. Pat. Appln. KOKAI Publication No. 2001-180353, for example, the load of an occupant in a seat of a vehicle is detected to recognize occupancy of the seat, in order to control an airbag and seatbelt retracting properly.
Further, an occupant discrimination control method is proposed to discriminate the state of occupancy of a seat that has a load receiving member, which is attached to the frame of a seat cushion by means of springs. According to this control method, loads that act at least on the front, rear, left-hand, and right-hand parts of the load receiving member are detected, and the sum total of the loads is obtained. This sum total is compared with a threshold value for occupant determination to discriminate the size of the occupant. Furthermore, the differences between the loads that act individually on the front and rear parts of the load receiving member and between the loads that act individually on the left- and right-hand parts are compared with their corresponding threshold values.
In some cases, however, a vehicle may be swung by the irregularities of a road surface, change of the course, etc., and a seated occupant may move his/her body as the vehicle runs. In the conventional occupant discrimination control method, as described above, the occupant is determined in accordance with only the detected values of the loads that act on the front, rear, left-hand, and right-hand parts of the seat cushion. According to this method, however, the occupant may be wrongly determined owing to vibration that acts on the vehicle and the occupant's behavior.